Eliane Radigue's Chry-Ptus is her very first piece for the modular synthesizer. It was composed in 1971 using a Buchla 100 which had recently been installed at NYU by Morton Subotnick. 'Chry-Ptus' (1971). Originally two tapes which were to be played simultaneously, with or without synchronisation, which does not affect the structure of the work, but creates changes in the game of sub-harmonics and overtones. Three variations on this piece were performed at the New York Cultural Center in 1971, with variations of amplitude and location modulation as well as synchronisation. Realized on the Buchla Synthesizer at the New York University.

The booklet contains a text by painter Paul Jenkins, who also realised the watercolor on the front cover, written on occasion of Radigue's first concert in New York, April 6th, 1971.

“It’s with the Buchla that I constructed Chry-ptus, a piece made up of two tapes with an analogue duration, 22 or 23 minutes, which could be played either simultaneously or with a slight time difference, so as to establish slight variations every time the piece was played. I spent the first months eliminating everything I did not want; I even used a notebook in which I tried to determine a writing system resembling chemical formulae.” Eliane Radigue